1. Field of the Invention
This invention relates to an intermediate transfer recording apparatus in which ink of an ink film is transferred onto an intermediate transfer film by means of a line thermal head to form a primary transfer image, and the primary transfer image is retransferred onto a disk-like transfer medium by means of retransfer means to thereby form an image on the transfer medium.
2. Description of the Related Art
Heretofore, the intermediate transfer recording apparatus in which ink of an ink film is transferred onto an intermediate transfer film comprising a long resin film consisting of resin such as polyethyleneterephthalate by means of a line thermal head to form a primary transfer image, and the primary transfer image is retransferred onto a transfer medium by means of retransfer means to thereby form an image on the transfer medium has been used as the recording apparatus for forming an image on various transfer media such as optical disks like CDs and cards.
In the case of a conventional intermediate transfer recording apparatus as described hereinabove, in the primary transfer image forming section, the line thermal head is brought into the head-down state in which the line thermal head is pressed on a platen roller with interposition of an ink film and an intermediate transfer film in this order, and some heating elements of the line thermal head are heated selectively based on image forming information while moving the ink film and the intermediate transfer film in this state to thereby partially melt or sublimate and transfer the ink of the ink film onto the intermediate transfer film. As the result, for example, a reverse image that is the primary transfer image for the area corresponding to an image recording region of a transfer medium is formed on the intermediate transfer film.
Furthermore, in the case where a multicolor image is formed on a transfer medium, a multicolor primary image is formed by means of so-called swing-back technique as described hereunder. A multicolor ink film on which a plurality of color ink regions are arranged so that different colors are repeated adjacently in a longitudinal direction is used as an ink film. At first, a reverse image of the first color ink that is carried on the multicolor ink film is formed on an intermediate transfer film. Then, a line thermal head is brought into a head-up state in which the line thermal head is separated from a platen, and the intermediate transfer film is moved reversely in this state. The reverse image formed with the first color ink is returned to the transfer position for start alignment, and a reverse image of the next color is transferred on the reverse image of the first color one on the other.
In detail, in the case where a full-color image is formed, a multicolor ink film on which a plurality of three-color ink regions, each of which consists of three colors, for example, C (cyan), M (magenta), and Y (yellow) are arranged in this order so as to be repeated adjacently in the longitudinal direction and which has color-discrimination marks on the boundary between different ink regions is used.
In detail, at first a register mark that has been marked previously on the intermediate transfer film is detected, and a C-color reverse image for the area corresponding to the recording region of the transfer medium is formed on the intermediate transfer film by using the register mark as the reference by use of a C-color ink region of the multicolor ink film. Next, the intermediate transfer film that has been moved in the primary transfer image forming operation is moved reversely and the C-color reverse image that has been formed on the intermediate transfer film is aligned, and an M-color ink region that is adjacent to the C-color of the multicolor ink film is aligned and an M-color reverse image is formed on the C-color reverse image that has been formed on the intermediate transfer film by use of an M-color ink region of the multicolor ink film. Subsequently, a Y-color ink region is aligned in the same manner as described hereinabove, a Y-color reverse image is formed additionally on the intermediate transfer film by use of a Y-color ink region of the multicolor ink film to thereby form a full-color primary transfer image for the area corresponding to the recording region of the transfer medium on the intermediate transfer film.
Thereafter, the intermediate transfer film is moved so that the primary transfer image that has been formed on the intermediate transfer film is moved to the position located just before the retransfer position. Then, the primary transfer image is registered with a transfer medium by use of a register mark formed on the intermediate transfer film, the primary transfer image that has been formed on the intermediate transfer film is melted or sublimated to retransfer and fix it on the transfer medium by heating and pressing by use of the retransfer means comprising a heating roller in the retransfer section to thereby form a desired image on the transfer medium.
However, the conventional primary transfer image formed on an intermediate transfer film only forms a primary transfer image for a area corresponding to a recording region of a transfer medium. Therefore, in the case where a primary transfer image is retransferred onto a disk-like transfer medium such as a CD, because the transfer medium is circular, the central portion of the primary transfer image of the intermediate transfer film is brought into contact with the disk at the start of retransfer, only the central portion is adhered on the transfer medium and both sides are not adhered. As a result, the peeling tension exerted on the intermediate transfer film is differentiated in the width direction of the intermediate transfer film. The adhered region of the primary transfer image on the transfer medium increases as the retransfer proceeds, and then decreases as the retransfer further proceeds after the middle point. As a result, the transfer condition for the transfer medium is not constant, good transfer condition cannot be obtained, and a good quality image cannot be formed on the transfer medium, which is disadvantageous.
The present invention has been accomplished in view of the abovementioned problem, it is the object of the present invention to provide an intermediate transfer recording apparatus that operates a process in which an adhesion region of an image is maintained constant throughout a retransfer operation from the start of retransfer to the end of the retransfer when a primary image of the intermediate transfer film is retransferred onto a disk-like transfer medium to bring about an optimal transfer condition to allow the formation of a good image recorded on the transfer medium.
To achieve the abovementioned object, an intermediate transfer recording apparatus in accordance with the present invention is characterized in that a dummy image is formed on a periphery of a retransfer image region on the transfer medium where the primary transfer image is not retransferred when the primary transfer image is formed on the intermediate transfer film. Because the abovementioned structure is employed, the dummy image is formed on a region where the primary transfer image is not retransferred on the transfer medium on the periphery of the retransfer image region corresponding to the transfer medium when the primary transfer image is formed on the intermediate transfer film. Thereby, the dummy image is in contact with an upper surface of a guide member of the transfer medium on the periphery of the transfer medium when the primary image is retransferred onto the transfer medium, and heated and pressed by means of heating means. The dummy image is retransferred in the same manner as in the case where the primary image is retransferred onto the transfer medium, and the retransfer region is maintained approximately constant throughout the retransfer operation, peeling tension exerted on the intermediate transfer film is approximately even in a width direction, and the primary transfer image is retransferred onto the transfer medium without changing of a transfer condition. As the result, an optimal retransfer condition can be obtained.
Furthermore, the intermediate transfer recording apparatus in accordance with the present invention is additionally characterized in that the dummy image is formed on the periphery of the primary transfer image with a predetermined space between the dummy image and the primary transfer image. Because the abovementioned structure is employed, retransfer of the dummy image onto the transfer medium is prevented even if registration between the primary image and the transfer medium deviates slightly when the primary image is retransferred onto the transfer medium.
Furthermore, the intermediate transfer recording apparatus in accordance with the present invention is additionally characterized in that an outside peripheral configuration of the dummy image is rectangular. Because the abovementioned structure is employed, the retransfer region is maintained constant throughout the retransfer operation from the start when the primary image is retransferred onto the transfer medium, and as the result a retransfer condition is optimized.
Furthermore, the intermediate transfer recording apparatus in accordance with the present invention is additionally characterized in that the dummy image is formed with a density lower than that of the primary transfer image. Because the abovementioned structure is employed, the power supplied to the thermal head can be reduced for the dummy image forming region, and as a result power consumption can be reduced.
Furthermore, the intermediate transfer recording apparatus in accordance with the present invention is additionally characterized in that the dummy image can be formed using at least one color ink layer of a multicolor ink film and the dummy image is formed with thermal energy that is smaller than that of the primary transfer medium. Because the abovementioned structure is employed, not only is power saved but also the time required to form the dummy image is shortened in comparison with the case in which all of the color ink layers are used for forming the dummy image.